1. Field of the Invention
The present invention relates to an information recording apparatus that records information acquired with a camera and/or a microphone provided in a vehicle into a recording medium.
2. Description of the Related Art
Drive recorders that are mounted in vehicles for recording images of an accident that occurs during driving have been put into practical use. Security devices including the so-called anti-theft function have also been put into practical use. Such devices capture images of the interior of a vehicle using a drive recorder as mentioned above upon detection of an abnormal condition such as a theft of a parked vehicle, including, for example, an impact applied to the vehicle and an illegal intrusion into the vehicle by a third party other the user of the vehicle, and records the captured images into a recording medium.
According to a first related art, the security device records images as an ordinary drive recorder when an ignition (IG) switch is on and the vehicle is in operation, i.e., during driving conditions. Even when the IG switch has been turned off, the drive recorder is operated to record images in order to prepare for an abnormal condition such as a theft (for example, see Japanese Unexamined Patent Publications JP-A 2006-227173 and JP-A 2006-302017). With the first related art, the drive recorder continues to capture images even in a case where the IG switch is off, i.e., the battery mounted in the vehicle is not being charged and no abnormal condition has occurred. The current consumption resulting, in particular, from operating a camera is very large, and therefore, the operation of the camera may cause exhaustion of the battery.
In view of such a problem, according to a second related art, images are captured for a predetermined time period and recorded into the recording medium, only when the IG switch is off and an abnormal condition has been detected by a G sensor, (for example, see Japanese Unexamined Patent Publication JP-A 2006-235732). Accordingly, it is possible to record images when an abnormal condition such as a theft occurs, while saving power consumption.
However, according to the second related art, images are recorded into the recording medium for a predetermined time period each time an abnormal condition is detected by the G sensor. Erroneous detections are inherent to a theft detection performed by sensors such as a G sensor. Large vibrations are generated, for example, in a case where a large vehicle such as a truck passes near a parked vehicle, a case where there is a heavy rain, or a case where some object hits the vehicle without any theft taking place. Such vibrations are detected in the same manner as a theft, and images are therefore recorded into the recording medium for a predetermined time. Since images are captured for a predetermined time period and the captured images are recorded into the recording medium even when there is no theft as described above, a large number of images that are unrelated to a theft are recorded into the recording medium owing to erroneous detections in a case where a vehicle is parked for a long period of time and the IG switch is off. Accordingly, the recording capacity for images that should be recorded during driving conditions is reduced, so there is the possibility that no image can be recorded when an accident occurs.